Theresa May is heading to Brussels later ahead of a critical EU summit to formally sign off the Brexit deal.
The prime minister will hold talks with top EU officials, before leaders of all 28 countries meet to endorse the agreement on Sunday.
However, Spain has said it will not attend unless a last-minute spat over Gibraltar is sorted out.
Even if the EU approves the deal, Mrs May must still persuade enough MPs to support it which could prove difficult.
Meanwhile the leader of the DUP – which Mrs May relies on for support in Parliament – will reiterate her opposition of the deal at her party conference later, after threatening to look again at the confidence and supply agreement with the Conservatives if it gets through Parliament.